Abstract
Rapid tremor migration (RTM) in subduction zones is a manifestation of complex fault-zone processes on the plate interface. Recent observations have revealed a large diversity of RTM patterns that are always associated with aseismic, shear strain at the interface. Small unstable asperities embedded in the stable shear zone are thus believed to originate tremor radiation during migration. Tectonic tremors have been recognized to occur where overpressured fluids exist. Spatial variations of fluid pressure may lead to non-linear diffusion processes with potentially large implications in tremor generation. Here, we show that pore-pressure waves are likely to exist in the plate interface, propagating with speeds and pathways similar to RTMs observed in different subduction zones including Guerrero, Mexico, where we introduce new high-resolution tremor locations and a RTM source physical model. These waves may explain the whole hierarchy of RTM patterns by producing transient reductions of the fault strength and thus secondary slip fronts triggering tremor during slow earthquakes.
Highlights
Rapid tremor migration (RTM) in subduction zones is a manifestation of complex fault-zone processes on the plate interface
A few of these models can explain most of the RTM patterns, none of them integrates a potentially critical element that seems to be always present in the episodic tremor and slip2 (ETS) environment: overpressured fluids
We explore a physical model capable to explain the diversity of RTM patterns as a result of transient perturbations of p traveling at the expected speeds and pathways along the fluid-saturated plate interface
Summary
Rapid tremor migration (RTM) in subduction zones is a manifestation of complex fault-zone processes on the plate interface. We show that porepressure waves are likely to exist in the plate interface, propagating with speeds and pathways similar to RTMs observed in different subduction zones including Guerrero, Mexico, where we introduce new high-resolution tremor locations and a RTM source physical model. These waves may explain the whole hierarchy of RTM patterns by producing transient reductions of the fault strength and secondary slip fronts triggering tremor during slow earthquakes. We explore a physical model capable to explain the diversity of RTM patterns as a result of transient perturbations of p traveling at the expected speeds and pathways along the fluid-saturated plate interface
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